1. Technical Field
The present disclosure relates to cutting of materials, and particularly, to a method of cutting bulk amorphous alloy using a laser.
2. Description of Related Art
Amorphous alloys, commonly referred to as metallic glass, are formed by solidification of alloy melts by cooling the alloy to a temperature below its glass transition temperature (Tg) before appreciable homogeneous nucleation and crystallization has occurred. More recently, a number of amorphous alloys with critical cooling rates (Rc) low enough to allow the formation of amorphous structure in thicker layers (those over 1 millimeter) have been produced. These are known as bulk amorphous alloys, or bulk metallic glass. Because the bulk amorphous alloys provide superior magnetic, mechanical, chemical, and other properties in comparison with the crystalline metals, many alloy compositions which can form an amorphous phase, such as Fe systems, Ni systems, Co systems, Al systems, Zr systems, and Ti systems, have been developed.
A variety of devices or components produced from Zr-based bulk amorphous alloy, such as golf clubs and hinges for mobile phones, has been developed. If the shape of the amorphous alloy component is relatively complicated, casting methods for fabrication are ineffective. Accordingly, it is necessary to cut the amorphous alloy component into a predetermined shape. Unfortunately, since amorphous alloys are extremely hard and brittle at room temperature and tend to fail suddenly when loaded in tension, conventional techniques that are used for cutting crystalline metals, such as die punching or wire cutting, may not be applicable to cut the amorphous alloys.
It is possible to cut completely through amorphous alloy using lasers. Referring to FIG. 12, a workpiece of Zr-based bulk amorphous alloy cut by a frequently used laser cutting method is shown. As seen, a high energy density of the focused laser tends to cause local vaporization of the workpiece, and molten or vaporized material tends to run or re-condense. This inevitably leads to the formation of cutting defects, especially burrs on a cut kerf. In addition, the amorphous alloy may crystallize to a crystalline state during the cutting process, so that the benefits of the amorphous state of amorphous alloy are lost.
Therefore, there is room for improvement within the art.